J.P. Instruments EDM 740 Pilots Guide - Manual (Page 22)

Page 22 Engine Data Management
LeanFind Mode
The EDM supports two methods of leaning; Rich Of Peak (ROP) and
Lean Of Peak (LOP). Note: you can set the power-up default to LOP or
ROP in the Pilot Program Mode but easily change modes during flight.
During traditional Rich Of Peak leaning, you’ll finalize the mixture to
about 20 to 80° rich of peak (depending on engine operating
requirements). However, with the advent of closely balanced injectors
(such as GAMI), it is possible to set the mixture lean of peak—thus
saving fuel and running the engine cooler. Teledyne Continental
recommends lean of peak for the Malibu. Both Rich Of Peak and Lean
Of Peak processes are described in detail in this manual.
Upon reaching cruise configuration, use the LeanFind mode to identify
the correct cylinder to reach peak EGT (for rich of peak this is the
FIRST to peak, for lean of peak this is the LAST to peak). To change
from one method to the other, just after activating LeanFind, hold STEP
and LF and the other method will be momentarily shown: ROP or LOP.
Release buttons after other method appears.
The following charts provide step by step guidelines in leaning your
engine, for both rich of peak and lean of peak modes: